1. Field of the Invention
The present invention relates generally to an inter-cell load balancing in a mobile communication system and, more particularly, to a method and apparatus for distributing traffic of a base station through the exchange of load information with an adjacent base station.
2. Description of the Related Art
From the early stage of providing voice-oriented services, mobile communication systems have evolved into high-speed and high-quality wireless packet data communication systems which provide data and multimedia services. Various mobile communication standards, such as High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA), Long Term Evolution (LTE), Long Term Evolution-Advanced (LTE-A), High Rate Packet Data (HRPD) of the 3rd Generation Partnership Project-2 (3GPP2), and IEEE 802.16, have recently been developed to support high-speed and high-quality wireless packet data communication services. In particular, the LTE system, which is a system developed to efficiently support high speed wireless packet data transmission, maximizes wireless system capacity by using various wireless access technologies. The LTE-A system, which is an advanced wireless system of the LTE system, has enhanced data transmission capability as compared to the LTE system.
Existing 3rd Generation (3G) and 4th Generation (4G) wireless packet data communication systems such as HSDPA, HSUPA, HRPD, and LTE/LTE-A employ an Adaptive Modulation and Coding (AMC) scheme, a channel-sensitive scheduling scheme, and the like to improve transmission efficiency. In the AMC scheme, a transmitter may adjust the amount of transmission data according to the channel state. For example, when the channel state is poor, the transmitter may adjust the reception error probability to a desired level by reducing the amount of transmission data, and when the channel state is good, the transmitter may adjust the reception error probability to a desired level by increasing the amount of transmission data, thereby efficiently transmitting a large amount of information.
To improve communication efficiency, methods of managing the load of a cell that a terminal accesses and managing the channel state are being developed. The general clustering technology for the management of the load of a cell is shown in FIG. 1. The general clustering technology forms a static cluster based on a Center Base Station (Center BS) which is a cluster header, as shown in FIG. 1. Internal information of the cluster may be collected in the Center BS through an X2-interface between Base Stations (BSs). The Center BS manages each cluster based on the information through a centralized scheme. In this instance, each cluster is independent and thus, managing the cooperation between the clusters is difficult when executing additional engineering designs or cooperation. In addition, due to a varying channel and interference environment, reforming a cluster may be difficult. Therefore, a technology for dynamically managing a cluster is needed.